Developmental changes in endogenous testosterone have sexually-dimorphic effects on spontaneous cortical dynamics

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Endocrinology

Background:

• Adolescence involves significant hormonal changes, including increased sex hormones like testosterone.
• Pubertal hormones influence brain development, but their impact on spontaneous cortical activity and sex differences remains understudied.
• Understanding these effects is crucial for comprehending adolescent brain maturation and executive function development.

Purpose of the Study:

• To investigate the effect of endogenous testosterone on spontaneous cortical activity in adolescents.
• To determine if sex modulates the relationship between testosterone and brain activity during this critical developmental period.

Main Methods:

• Resting-state magnetoencephalography (MEG) and structural MRI were used in 71 typically-developing adolescents (ages 10-17).
• Saliva samples analyzed testosterone levels; MEG data processed for power spectral density in five frequency bands (delta, theta, alpha, beta, gamma).
• Vertex-wise ANCOVAs identified testosterone effects and sex by testosterone interactions, controlling for age.

Main Results:

• Robust sex differences were observed in how testosterone modulates spontaneous delta, beta, and gamma activity.
• These testosterone-sex interactions were primarily located in frontal cortices.
• A notable shift in correlation direction occurred between low (delta) and high (beta/gamma) frequencies, with differing patterns for boys and girls.

Conclusions:

• Testosterone levels are uniquely associated with the development of spontaneous cortical dynamics in adolescence.
• The relationship between testosterone and brain activity during adolescence shows distinct developmental patterns in males and females.
• These findings highlight sex-specific neurodevelopmental trajectories in regions critical for executive functioning.